Among the biggest gainers was Ceres Inc., soaring 82 percent $3.73. The Thousand Oaks developer of genetically modified seeds for biofuel crops is expected to report strong harvest yields for crops now being tested in Brazil, a key market.

Dole Food Co. rose 30 percent to $12.78. Chief Executive David Murdock made an unsolicited $12-a-share offer to buy the 60 percent of Westlake Village fresh food and vegetable company that he does not already own.

Motorcar Parts of America Inc. rose 20 percent to $7.40. The Torrance rebuilder of alternators and starters finally wrote off a failed 2011 acquisition of a Canadian parts builder and related affiliates, which were broken off from the company. The companies then filed for bankruptcy with plans to liquidate.

Among the decliners was Internet hotspot provider Boingo Wireless Inc., which fell 6 percent to $6.42.